arm: Allow lr to be saved by board code

[u-boot] / arch / arm / include / asm / system.h

diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 89f22946895301b09a183ead75503ae4dff0f1b2..7820486df00e50405c31d079c497ecdb6a562ed0 100644 (file)
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -142,6 +142,21 @@ void flush_l3_cache(void);
 
 #ifndef __ASSEMBLY__
 
+/**
+ * save_boot_params() - Save boot parameters before starting reset sequence
+ *
+ * If you provide this function it will be called immediately U-Boot starts,
+ * both for SPL and U-Boot proper.
+ *
+ * All registers are unchanged from U-Boot entry. No registers need be
+ * preserved.
+ *
+ * This is not a normal C function. There is no stack. Return by branching to
+ * save_boot_params_ret.
+ *
+ * void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3);
+ */
+
 #define isb() __asm__ __volatile__ ("" : : : "memory")
 
 #define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");